French onion soup is so simple, so inexpensive, and so classic. The sweet onions, gooey cheese, and soaked bread is so comforting, eating it is like getting a warm hug from the inside. Slicing the onions for this dish is a bit of a chore - but it’s French onion soup, so I guess you expected to slice onions? And caramelizing them to achieve the deep, nutty brown sweetness of your onion soup dreams takes time, but largely unattended time. Your patience will be well rewarded.

I pulled this recipe from The Food Lab by J. Kenji López-Alt, a heavy tome of a book detailing everything from how to make canned beans taste good to how to make perfectly crispy roasted potatoes (outlining several trials leading to success). If you like understanding the science behind cooking, I highly recommend - this is a book for geeks who like to eat good food. Mr. López-Alt explains that your onion eating needs are best served by slicing onions from tip-to-tip (or, if you want to think of your onion as a globe, from pole-to-pole). So that’s what we do here, for 5 pounds or 7 cups of onions. I suggest that step one is sharpening your knife (or grabbing your mandoline).

Once sliced, this abundance of onions goes into a dutch oven with some butter and salt to sweat out over very low heat for 2 hours. Over this time, the onions collapse down to a more reasonable amount, surrounded by their sugary juices. The heat goes up, the water evaporates, and the onions turn sweet and deeply browned. Simmer with some fresh herbs, sherry, and chicken stock, and your soup base is done. A chunky slice of baguette, a healthy dose of shredded cheese (metaphorically speaking), and trip to the broiler officially make this French onion soup.

Make sure to use broiler-proof bowls for this - crocks or ramekins or whatnot. In a pinch, you could cover a sheet pan with some foil, broil the cheese directly onto the bread, and then add it to your soup. But then you’d probably want to make sure the soup is piping hot and add some additional cheese to melt into it… because, you know, cheese.

French Onion Soup

Time: 3 hours || Servings: 4 || Source: The Food Lab

• Yellow onions - 5 lbs, about 7 cups, thinly sliced pole to pole

• Butter, unsalted - 4 tbsp

• Salt - 1 tsp

• Sherry - ¼ cup

• Chicken stock - 6 cups

• Bay leaves - 2, fresh or dried

• Thyme - 6 sprigs fresh, or 1 tsp dried

• Gruyere or Swiss cheese - 8 oz, about 2 cups grated

• Baguette - sliced 1/2 inch thick, either a day old or toasted

Use a large Dutch oven or other heavy bottomed pot with a tight fitting lid. Place pot over medium heat and melt butter. Add onions and the salt. The pot will be full of onions - it will seem ridiculous, but it will cook down to a reasonable amount over time. Cook for about 5 minutes, stirring now and then with a wooden spoon, until the onions have begun to soften and wilt a bit. Cover the pot with the lid (if it’s not tight fitting, cover with aluminum foil and then the lid) and reduce to the lowest heat possible. Cook for 2 hours, giving the onions a stir every 45 minutes or so, until the onions are completely tender.

Remove the lid and foil, if using, and increase the heat to medium-high. The onions will have released a lot of water. Cook for about 15 minutes, stirring frequently, until the liquid has evaporated and you see a brown crust starting to form on the bottom of the pot. This is the start of your caramelization! Deglaze the pan by adding 2 tbsp of water and scrape up the brown crust with a wooden spoon. Distribute the onions evenly over the bottom of the pot, then let it cook for another 5 minutes, undisturbed, until the brown crust develops again. Repeat this pattern of deglazing and undisturbed cooking until the onions become a deep golden brown and taste sweet and delicious. This might take 4 or 5 total cycles.

Once your onions reach the desired color, add the sherry, chicken stock, bay leaves, and thyme to the pot. Bring the liquid to a boil, then reduce to a simmer. Simmer, uncovered, for 15 minutes. The stock will reduce slightly and turn dark. Taste and season with salt and pepper. Discard the bay leaves and the thyme sprigs, if using.

Heat the broiler. Place four broiler-proof bowls on a baking sheet (I used large ramekins). Distribute soup among bowls, top with a slice of baguette and the shredded cheese. Slide the pan under the broiler for about 5 minutes, keeping an eye on it, until the cheese is melted and turning brown in spots. Serve piping hot.

Note: After the 2 hours of low heat, it won’t hurt your onions to allow them to sit without heat for a couple of hours before moving on to evaporating the remaining water and caramelizing them.